There are 13 suits in total you'll need for this achievement.
3 suits are given to you at the start of the game.
2 suits are story-related and are given to you for defeating Black Cat and Carnage.
6 suits are awarded for completing the story hideout and the 5 optional hideouts.
1 suit is awarded for completing all 15 races.
1 suit is awarded for completing all 12 combat challenges.
You will also earn the "State of the Art" achievement for collecting all the concept art while completing these. You'll unlock all of the concept art by completing 11 races and 11 combat challenges.